Dowel pinning for feline metacarpal and metatarsal fractures.

The goal of this retrospective study was to describe dowel pinning, and to compare the results of osteosynthesis and external coaptation of metacarpal and metatarsal fractures in cats. Evaluation of the medical records of 351 cats yielded 63 cats treated with dowel pinning, 35 cats treated with external coaptation and 14 cats treated with both methods within the same limb. All of the cats had been re-evaluated at an average of 2.8 years (six months - 15 years) postoperatively. Dowel pinning was superior to external coaptation when all fractured bones of a limb could be pinned. When internal fixation of multiple fractures was not feasible in all fractured bones due to comminution or fragments that were too short to pin, the outcome was not significantly different from cases treated with external coaptation alone. Malunion was seen in 16% of fractured bones in cats treated with external coaptation and occurred secondary to implant bending in 3% of fractured bones treated with dowel pinning. The latter refers to one operated cat, which had four metacarpal fractures in the same limb. Radiographs taken at re-evaluation showed implant migration within the medullary canal in two cats, although neither showed any signs of non-union or lameness. Non-union was seen in one operated cat, in which the fracture (MC IV) could not be completely reduced with a K-wire. Osteomyelitis did not occur. Dowel pinning is an easy, inexpensive and effective technique for repair of metacarpal and metatarsal fractures in cats.     

Supracondylar femoral fractures in 159 dogs and cats treated using a normograde intramedullary pinning technique

Three separate studies that collectively represent 107 dogs and 52 cats with supracondylar femoral fractures are presented. The animals were treated using a normograde intramedullary pinning technique at the Norwegian School of Veterinary Science during the period 1964 to 1993. The surgical technique involves insertion of one or two intramedullary pins normograde from the stifle joint without passing their proximal end proximal to the level of the femoral neck. The results of treatment were obtained for 73 dogs and 39 cats. Of these cases, 58 dogs (79.5 per cent) and 32 cats (82.1 per cent) were found to be free of lameness after the completion of treatment. Differences in the results of treatment, based on species or size, were not found. Of all cases in which the results of treatment were known (n = 112), complications were recorded in nine animals (8.0 per cent). Infection and instability were the most common complications, affecting four and three cases, respectively.     

Standing surgical repair of propagating metacarpal and metatarsal condylar fractures in racehorses

REASONS FOR PERFORMING STUDY: Repair of spiral and long diaphyseal metacarpal and metatarsal fractures under anaesthesia can be problematic and associated with a high incidence of complications, including fracture propagation necessitating euthanasia. OBJECTIVE: To report on a practical repair technique for which general anaesthesia is not required. METHODS: Thirteen racehorses with a spiral/propagating condylar fracture had the fracture repaired using local anaesthesia and sedation, without the need for general anaesthetic. RESULTS: Ten of the horses returned to training and 8 raced again. Two horses were retired directly to stud. One horse had propagation of the fracture 3 days post surgery, and was subjected to euthanasia. CONCLUSIONS AND POTENTIAL RELEVANCE: Results achieved were comparable to those gained using standard repair techniques under general anaesthesia. The described technique removes the need for general anaesthesia for repair of selected condylar fractures.     

Nuclear scintigraphic evaluation of third metacarpal and metatarsal bone fractures in three horses

Nuclear scintigraphy was used to evaluate healing of third metacarpal bone (MC III) fractures in 2 horses (horses 1 and 2) and a third metatarsal bone fracture in 1 horse (horse 3) after stabilization of each fracture with 2 broad dynamic compression plates. In horse 1, the fracture had uniform uptake of 99mTc methylene diphosphonate on days 1, 15, and 30 after surgery. The fracture healed, and the horse was discharged from the clinic on day 52. In horse 2, a 6-cm photopenic region (ie, area of low radioactivity) was seen over the diaphysis of MC III on day 3. The region persisted and became more distinct by day 32. The diaphysis of MC III sequestered, and horse 2 was euthanatized on day 44. In horse 3, vascularity was seen bridging the fracture on day 5, with a 3-cm photopenic region over the dorsal diaphysis of the third metatarsal bone. By days 18 and 32, uptake of 99mTc methylene diphosphonate in the region had increased, indicating vascularization of the site. the fracture healed, and horse 3 was discharged from the clinic on day 47. Our findings indicated that serial nuclear scintigraphy can be used to evaluate fracture vascularization after surgery in horses.     

Long incomplete longitudinal fractures of the third metacarpal and metatarsal bone in horses

Five horses with long incomplete longitudinal fractures of the third metacarpal bone and three horses with similar fractures of the third metatarsal bone were examined. In three of the metacarpal fractures a long incomplete fissure extended proximomedially, in association with the more common lateral condylar fracture of the third metacarpal bone, and in the other two cases the fracture originated from the medial aspect of the distal articular surface. In the three horses with fractures of the third metatarsal bone the fractures had a consistent spiral configuration.     

An in vitro biomechanical investigation of an intramedullary nailing technique for repair of third metacarpal and metatarsal fractures in neonates and foals

OBJECTIVE: To evaluate a dorsoproximal extra-articular approach for insertion of 8.25-mm, solid-titanium, intramedullary (IM) interlocking nails into ostectomized foal third metacarpal (MC3) and third metatarsal (MT3) bones; to compare the monotonic mechanical properties of IM nail constructs with paired intact bones; and to determine the effects of age, body weight, fore- or hindlimb, and left or right limb on the mechanical testing variables. ANIMAL OR SAMPLE POPULATION: Twenty bone pairs (10 MC3, 10 MT3) collected from 10 foals of various weights and ages. METHODS: One bone from each pair was randomly selected to be ostectomized and stabilized using an 8.25-mm, solid-titanium IM nail, and four 3.7-mm titanium interlocking screws (construct). Constructs and contralateral intact bone specimens were tested in axial compression and palmaro-/plantarodorsal (PD) 4-point bending. Monotonic mechanical properties were compared between intact specimens and constructs with an ANOVA; significance was set at P <.05. RESULTS: Nail insertion caused bone failure in 6 MC3 and 2 MT3. In general, mean mechanical testing values indicated that intact specimens were significantly stronger and stiffer than constructs for all age and weight ranges when tested in compression and PD 4-point bending (P <.05). Bone strength and stiffness of intact specimens tested in compression and bending tended to increase linearly with age and weight. CONCLUSION: IM interlocking nail fixation of gap-ostectomized MC3 and MT3 with 8.25-mm IM nails and 3.7-mm interlocking screws did not achieve sufficient strength or stiffness to be recommended as the sole means of repair for comminuted MC3 and MT3 fractures in young foals. CLINICAL RELEVANCE: IM interlocking nail fixation of foal cannon bone fractures may be useful to decrease soft-tissue disruption at the fracture site; however, there is a risk of bone failure associated with extra-articular insertion. This method should be combined with other forms of external coaptation for added stability in axial compression and PD bending.     

Treating pedal shortening in a dog by metatarsal distraction osteogenesis

A five-month-old, male German shepherd dog was presented with a left hindlimb deformity. Wearing a cast for a prolonged period to treat left metatarsal fractures at eight weeks of age had resulted in physeal closure of the calcaneus, metatarsals and phalanges. Hyperextension of the phalanges and ulceration of the plantar skin proximal to the main tarsal pad were seen. The left foot was 40 mm shorter than the right. At seven months of age, a modified circular external skeletal fixator (CESF) was used to perform distraction osteogenesis of the metatarsal bones for 28 days. The CESF apparatus was removed after eight weeks when there was radiographic consolidation of regenerate bone. At follow-up evaluations four and 12 months after surgery, the phalangeal hyperextension and plantar skin ulceration had resolved. No lameness was detected.     

Macroscopic changes in the distal ends of the third metacarpal and metatarsal bones of Thoroughbred racehorses with condylar fractures

OBJECTIVE: To determine changes in the distal ends of the third metacarpal and metatarsal bones (MCIII and MTIII) of Thoroughbred racehorses that had sustained a catastrophic condylar fracture during high-speed exercise. SAMPLE POPULATION: Fractured and contralateral MCIIIs and MTIIIs from 11 Thoroughbred racehorses that sustained a displaced condylar fracture during racing, both MCIIIs from 5 Thoroughbred racehorses euthanatized because of a catastrophic injury other than a condylar fracture, and both MCIIIs from 5 horses of other breeds that had not been professionally trained or raced. PROCEDURE: Macroscopic observations were made of the distal ends of the bones before and after digestion of the articular cartilage with NaOH. RESULTS: In all 11 racehorses with a displaced condylar fracture, the fracture was associated with a branching array of cracks in the condylar groove. In this region, fracture margins were smooth, and there was loss of subchondral bone. Comminution of the dorsal cortex was also seen. Parasagittal linear wear lines in the articular cartilage, erosions in the articular cartilage of the condyles, loss of the underlying subchondral bone, and cracking of condylar grooves were all more severe in the Thoroughbred racehorses than in the horses that had not been professionally trained or raced. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that condylar fractures in horses are pathologic fatigue or stress fractures that arise from a preexisting, branching array of cracks in the condylar groove of the distal end of MCIII or MTIII.     

Metacarpal and metatarsal fractures in dogs

Metacarpal fractures were more common than metatarsal fractures in this retrospective study of 37 dogs. Fractures of one metacarpal or metatarsal bone occurred In 24 per cent of the dogs, two metacarpal bones in 16 per cent, three metacarpal or metatarsal bones in 19 per cent, and four metacarpal or metatarsal bones in 41 per cent. Eighty-seven per cent of the dogs with fractures of four bones had fracture displacement or malalignment of at least one digit. Progressive fracture healing usually occurred Irrespective of stabilisation method. For malaligned fractures, however, external coaptation did not consistently improve alignment. Fracture alignment was consistently Improved by open reduction and internal fixation of acute fractures with bone plates. Fractures of four bones occurred most often In the distal metacarpus as opposed to the proximal metatarsus. Therefore, open reduction and internal fixation may be more commonly indicated for severe metacarpal fractures, because fracture displacement or axial1 malalignment was significantly associated with fractures of the mid or distal regions of the metacarpus or metatarsus (P=0.052).     

Aetiopathogenesis of parasagittal fractures of the distal condyles of the third metacarpal and third metatarsal bones--review of the literature

Fractures are the cause of considerable morbidity and mortality among Thoroughbred racehorses. A significant proportion of these injuries occur in the absence of any particular traumatic incident. Evidence of prefracture pathology interpreted as fatigue damage has been identified in some such cases, but the aetiology of many of these so-called 'spontaneous' fractures remains obscure. Parasagittal fractures of the third metacarpal (McIII) and third metatarsal (MtIII) bones are one of the more common fractures to affect Thoroughbred racehorses. The configuration of each of these fracture types is highly consistent, suggesting a predisposition of the bones to these injuries. Several theories have been proposed to explain the aetiopathogenesis of these fractures although none has so far stood up to critical examination. The current paper reviews the literature relating to parasagittal fractures of McIII and MtIII.     

Surgical management of complete diaphyseal third metacarpal and metatarsal bone fractures: Clinical outcome in 10 mature horses and 11 foals

Reasons for performing study: Osteosynthesis of third metacarpal (McIII) and third metatarsal (MtIII) bone fractures in horses is a surgical challenge and complications surrounding the repair are common. Retrospective studies evaluating surgical repair, complications and outcome are necessary to increase knowledge and improve success of long bone fracture repair in the horse. Objectives: To evaluate clinical findings, surgical repair, post operative complications and outcome of 10 mature horses and 11 foals with McIII or MtIII fractures that were treated with open reduction and internal fixation (ORIF). Methods: Medical records were reviewed and follow‐up information obtained by means of radiographs and/or telephone questionnaire. Results: Survival was achieved in 62% of the horses (3 mature/10 foals). On long‐term evaluation (>6 months) 11 horses (2 mature/9 foals) were fit for their intended activity, one mature horse had a chronic low grade lameness, and one foal was lost to follow‐up because it was sold. The main fracture types were simple transverse (33.3%) or simple oblique (28.6%) and 71.4% of the fractures were open, 3 Type I (one mature/2 foals) and 12 type II (7 mature/5 foals). The preoperative assessment revealed inadequate emergency treatment in 10 horses (5 mature/5 foals; 47.6%). Survival rate of horses with open fractures was 12.5% (1/8) in mature and 85.7% (6/7) in foals. Post operative incisional infection (4 mature, 3 foals) was only managed successfully in 2 foals. Fracture instability related to inadequate fracture fixation technique occurred in 4 horses (all mature) and was always associated with unsuccessful outcome. Conclusions: Age, bodyweight and infection are strongly associated with outcome in treatment of complete McIII/MtIII fractures. Clinical relevance: Rigid fixation using plates and screws can be successful in treatment of closed or open, complete diaphyseal McIII/MtIII fractures in mature horses and foals. Instable fixation, infection and a bodyweight >320 kg are major risk factors for unsuccessful outcome.     

Results of treatment of 145 fractures of the third metacarpal/metatarsal condyles in 135 horses (1986-1994).

The objectives of this study were to correlate condylar fracture characteristics and type of treatment with subsequent capacity for athletic ability, and to determine the characteristics of healing that affect prognosis after fracture fixation. Medical records, post operative radiographic studies and race records were examined for 135 horses sustaining 145 fractures. Sixty-five percent of horses overall started in a race post injury (SPI) in a mean time of 9.7 months with a mean of 13.7 races post injury. Having raced pre-injury did not confer an advantage to starting post injury, though nonstarters pre-injury tended to take longer to return. For horses starting pre- and post injury, 66% improved or maintained their race class level after injury, whereas 64.2% decreased their race earnings post injury. Eighty-five percent of the fractures received internal fixation, of which 70% were complete fractures. Eighty-seven percent of horses with incomplete-nondisplaced fractures treated conservatively raced post injury. The percent SPI for incomplete-nondisplaced, complete-nondisplaced and complete-displaced fractures treated with internal fixation were 74%, 58%, and 60%, respectively. Males (72%) raced post injury more frequently than fillies (53%), and may represent a truer probability of SPI. Spiral fractures tended to take longer until their first start (mean 13.3 months). Fifty-two percent of horses with articular fragments were able to race post injury. Horses were more likely to start if 2-4 month radiographic healing revealed no evidence of the fracture except the presence of lag screws. Based on this series of cases, the majority of horses, with proper treatment, were able to return to racing regardless of fracture characteristic. Prognosis appeared to be affected by the severity of the injury to the joint, the presence of articular comminution and the quality of surgical repair.     

Evaluation of a polyurethane jugular catheter in cats placed using a modified Seldinger technique

OBJECTIVE: To describe and evaluate the placement of a new design of polyurethane jugular catheter in cats using a modification of the technique of Seldinger. The maintenance and use of these catheters for repeated blood sampling over several days in healthy and diabetic cats is reported. PROCEDURE: Thirty polyurethane jugular catheters were placed in 10 clinically healthy cats and 10 cats with diabetes mellitus using the modified Seldinger technique. Catheters were placed while the cats were under general anaesthesia. RESULTS: The catheters remained in place for a range of 2 to 14 days (median 5 days) with no major complications. In all cats patency of the catheters was maintained until removal. All cats examined had patent jugular veins when assessed 4 or more weeks after the catheters were removed. CONCLUSIONS: These polyurethane jugular catheters, when placed by a modified Seldinger technique, are effective and safe in cats, and jugular patency returns after the catheters are removed.     

Osteochondritis dissecans of the sagittal ridge of the third metacarpal and metatarsal bones in horses

Osteochondritis dissecans of the sagittal ridge of the third metacarpal and metatarsal bones was diagnosed in 8 horses during an 18-month period. Seven of the horses were less than or equal to 2 1/2 years old. Synovial distention of the affected fetlock joints and a pain response to fetlock flexion were typical findings. Lameness predominated in 1 limb at a trot, although fetlock flexion frequently elicited lameness in other affected limbs. Radiography revealed bony lesions (flattening, erosion, or fragmentation) of the sagittal ridge in at least 2 fetlock joints in all horses. The onset of signs was not correlated with the severity of radiographic changes in all horses.     

Comminuted long bone fractures in cats caused by pneumatic gun shot and repaired using the external fixator "tie-in" technique

Five cats with femoral fractures caused by pneumatic gun shot wounds were treated using intramedullary pin/external skeletal fixation "tie-in" (IM/ESF tie-in) technique between 1997 and 2005. Clinical and radiographical examinations were used to assess bone healing, limb function recovery and complications. Clinical results as well as fracture healing were excellent in all five cats. The study showed that the IM/ESF tie-in technique can be used in cats for the treatment of comminuted femoral fractures caused by pneumatic bullets.